The invention relates to chairs in general, and more particularly to improvements in swivel chairs, for example, of the type disclosed in commonly owned U.S. Pat. No. 4,603,905 granted Aug. 5, 1986 to Felix Stucki for "Control mechanism for an adjustable chair or the like".
It is known to provide an office chair, particularly a swivel chair, with an adjustable seat and with a back rest which is articulately connected to a frame on top of a support of the leg of the chair. As a rule, the seat and the back support are provided with cushions which overlie suitably configurated shells and are or can be articulately connected to each other. The chair is provided with a discrete frame which is mounted on the support and is connected with the seat and back rest. The purpose of the frame is to transmit forces between the support on the one hand and the seat and back support on the other hand, especially to transmit forces which develop when the chair is occupied by a person. A drawback of the frame is that it contributes to the cost and bulk of the chair as well as that is detracts from the appearance of the chair. Moreover, the provision of a frame contributes to complexity of the adjusting mechanism which is normally provided to bring about changes in the positions of the seat and/or back rest relative to the support and/or relative to each other.
A typical discrete frame on top of the support of the leg is disclosed, for example, in German Offenlegungsschrift No. 29 25 520. The frame is directly affixed to the underside of the seat and is pivotally connected to the frame members of the back rest. The frame and other parts of the chair which is disclosed in this publication take up a substantial amount of space beneath the seat as well as behind the back rest. This detracts from the appearance of the chair.
German Utility Model No. 77 21 954 discloses a modified swivel chair wherein the support at the upper end of the upright column of the leg carries a discrete frame having a first part which is articulately connected to the front portion of the seat and a second part which is articulately connected to the rear portion of the seat. The rear portion of the seat is rigidly or movably connected with a one-piece back rest. The parts beneath the two-piece seat occupy a substantial amount of space and detract from the appearance of the chair.
A further conventional swivel chair is disclosed in German Utility Model No. 84 17 429. The back rest of this chair is located in front of a large frame which carries an adjusting mechanism for the back rest, and such frame is further coupled to a frame at the underside of the seat. The two frames are mounted on a further frame on top of the upright column of the leg. This chair exhibits the drawbacks of the aforediscussed conventional chairs.